| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | could be [verb] to | 892 |
|
| 2 | could be [vb pp] to | 869 |
|
| 3 | [modal v] be extended to | 136 |
|
| 4 | [vb mod] be extended to | 136 |
|
| 5 | could be extended [prep] | 35 |
|
| 6 | could be extended [prep] | 35 |
|
| 7 | could be extended to | 23 |
|
| 8 | could be extended to | 23 |
|
| 9 | could [be] extended to | 23 |
|
| 10 | could be extend to | 23 |
|
